ABSTRACT
Plant immunity: Immunity in higher plants consists of an immune state of systemic acquired resistance (SAR) that follows a local infection by pathogenic microorganisms that leads to lesions with death of host cells. SAR encompasses a broad spectrum of bacterial, viral, and fungal agents, as well as the infective pathogen. Various SAR genes encode numerous microbicidal proteins induced by endogenous chemicals that include salicylic acid, which combines with a catalase to increase H2O2, which may facilitate defense. (Figure 27.1)
Systemic acquired resistance (SAR) is an immune state of a plant, which enables it to resist attack by a broad range of pathogens. Elevated concentrations of nitric oxide (NO), salicylic acid, and pathogenesis-related (PR) proteins mediate SAR. See plant immunity.
